/*
 * yauosk - Yet Another Useless Operating System Kernel
 *
 * Copyright (c) 2009-2010 Matteo Cicuttin
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 * derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * memmove: move blocks of memory. The blocks can overlap.
 * Returns the original dst;
 */

#include <sys/types.h>

void *
memmove(void *dst, const void *src, size_t bytes)
{
	const char *s;
	char *d;
	
	s = (char *) src;
	d = (char *) dst;
	

	/* the last part of s overlaps with first part of d: backward copy */
	if ( s < d && s + bytes > d)
	{
		s += bytes;
		d += bytes;
		while ( bytes-- )
			*--d = *--s;
	}
	else /* otherwise use forward copy */
	{
		while ( bytes-- )
			*d++ = *s++;
	}
	
	return dst;
}

/*
 * memset
 */
void *
memset(void *mem, int c, size_t bytes)
{
	char *m = (char *)mem;
	
	while (bytes--)
		*m++ = c;
	
	return mem;
}

/*
 * bcopy
 */
void
bcopy(void *dst, const void *src, size_t bytes)
{
	memmove(dst, src, bytes);
}

/*
 * bzero
 */
void
bzero(void *mem, size_t bytes)
{
	memset(mem, 0, bytes);
}
